MAXIMUM UTILIZATION OF KARKADE IN FOOD PROCESSING

Abstract

Roselle or karkade (Hibiscus sabdariffa L.) is one of the valuable plants grown in tropical and subtropical regions. Roselle calyces are commonly used to make herbal tea as well as a natural food color additive. However, Roselle seeds are usually discarded as by–product, while it could be used as a promising source of nutritious, functional compounds and edible oil. It is worth mentioning that roselle leaves has considerable amount of nutrients and ranks high in quality comparable to other plants. So this study aimed to focus and shed light upon the nutritional value of roselle plant as an un-traditional source and to evaluate its possibility for utilization as a supplementary food product. 1- The effect of blending sunflower oil with roselle seeds oil on autoxidation. 2- The effect of the replacement of soybean flour with roselle seeds cake powder at levels 0, 25, 50, 75 and 100% on the nutritional and quality properties of beef burger. 3- The effect of the partial replacement of wheat flour with either from roselle cake powder (0, 10, 20 and 30%) or roselle leaves powder (0, 2.5, 5 and 7.5%) on the nutritional quality properties of biscuits, were studied. The obtained results could be summarized as follow A. Approximate analysis of roselle plant 1- Roselle seed, seeds cake and leaves are rich source of valuable nutrients, i.e., protein (12.32 – 29.06%), lipids (4.45 – 27.83%), ash (5.53 – 15.13%) and crude fiber (14.52 – 20.53%) as well as higher content of essential minerals. Potassium, calcium and phosphorus were detected at high concentration in roselle parts, they ranged between 7.94 to 46.30 mg/g, 5.29 to 28.80 mg/g and 3.23 to 22.10 mg/g; respectively. The other studied elements were determined at low values. Total phenolic compounds ranged between 155.04 to 3288.33 ppm as gallic acid, so it was the highest in roselle leaves being 3288.33 ppm followed by stem (2086.78 ppm). 2- The sequence of amino acids profile of the roselle seeds demonstrated that, glutamic acid and leucine had the highest concentrations in roselle seeds, 18.90% and 6.80% for non-essential and essential amino acids; respectively. The total non-essential and essential amino acids concentration were found to be 62.60% and 34.80%; respectively. Most of the amino acids compared favorably with FAO/WHO standards.